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Picture of How to Build Bottle Rocket w/ Tennis Ball Parachute

Step 1: Gather Materials

Picture of Gather Materials
Materials Needed For Project:

-Tennis Ball
-Bottle(s)
-Fins made of your cardboard
-Garbage bag for Parachute
-Tape 
-String
 
why have to be a tennis ball?
I mean it's too heavy for a simple water-pumped- by-bike-pumper-rocket
should i or can i use a small rock instead of a tennis ball?
the rocket is already heavy you know
texabyte5 years ago
why do you need the tennis ball?
I have not built one of these, but I think the tennis ball acts as a gravity triggered release mechanism for the parachute. It pulls or pushes it out.

If the parachute remains in a dry section of the device, talcum powder may be a cheap and effective material that helps the plastic "chute" slide out easier.
rickharris5 years ago
This is driving me nuts!!! :-0 several instructable - all similar - apparently from the same set of master instructions call for the use of a tennis ball in the construction of the water rocket BUT it never gets used. Has the makings of an episode of NCIS!